Leben, 33, announced the end of his fighting career on The MMA Hour. He fought 22 times for the UFC during a near nine-year span, compiling a 12-10 record.

He last fought at UFC 168 on December 28 in Las Vegas, where he retired on his stool between the first and second rounds against Uriah Hall. Leben (22-11) said he contemplated retirement immediately, but decided to sleep on it first.

"After the fight, I wanted to re-evaluate things and make sure the decision wasn't based on emotion," Leben said."Yes, I can say I am retired from competing in mixed martial arts."

Leben intends to remain in the sport as a coach. He posted on his official Twitter account on Sunday that he had accepted a "dream job" as an instructor at Victory MMA and Fitness in San Diego.

He first fought professionally in 2002 and joined the UFC in 2005 as a member of the inaugural season of The Ultimate Fighter reality series. He started his UFC career 5-0, before suffering a loss to then-UFC newcomer Anderson Silva in June 2006.

Leben struggled with drug and alcohol use throughout his career and was twice suspended for positive drug tests, in 2008 and 2011. After testing positive for painkillers in 2011, he enrolled himself into a rehabilitation program.

The loss Leben suffered in December was his fourth in a row and dropped him to 1-5 in his previous six appearances. He enjoyed arguably his best year in 2010, when he recorded three consecutive wins, two of which occurred within a two-week span.

"It was a fantastic, wonderful ride," Leben said. "I definitely had highs, lows, ups and downs. I'm starting to realise that for me, it might be time to get on more of the coaching side of things."